T2 has this silly endgame plot where, if you destroy the One Ring, you can go into the Void after killing Morgoth and battle Melkor's true form there. So if you wield the one then presumably Melkor is still in charge, just with you as a proxy. What can I see, he's a schemer. :P

(Also there's this thing where you have to kill some kind of Lovecraftian evil spirit with an unpronounceable name to get the Flame Imperishable which lets you imbue an item with magical power to bypass Melkor's magical barriers, in the process giving you a weapon or armor of ridiculous power. If Tolkien were still alive, T2 would absolutely make him cry.)